40 XUJ

+ ++

30

20

70

~ 80 90

100 110 120 130 140

LENGTH

IN

MILLIMETERS

Fig. 19.—Clypeaster rosaceus ^dalli (Twitchell). Height relative to length of test.

Diagnosis.

—

^Subspecies characterized

by

^{broad test.}

Material.

—

Sixty-nine specimens.

Shape.

—

^{Large, largest specimen 145}

^mm

^{long, smallest 70}

^mm;

elongate with width varying

from 79

to

90

percent of the length;

height very variable (text figs. 19, 21, 22), varying

from 36

to 57 percent of the length; marginal outline variable, angularly penta- gonal in

some

specimens, smoothly pentagonal in others; anterior

margin

pointed, posterior truncated, sides indented slightly in all but three specimens_; petals strongly inflated in

some

specimens, slightly inflated in other, adorally test greatly depressed in area immediately

around

peristome.

28

SMITHSONIAN MISCELLANEOUS COLLECTIONS

VOL. 145 Apical system.

—

^Central, monobasal, madreporite pentagonal, geni- tal pores small, five, varying in position

from

adjacent to

madre-

porite, or far distant, occurring in interambulacra.

Ambulacra. —

^{Petals all similar, broad, closed, long petals II, III,}

IV

extending almost to margin, petals

V,

^I over two-thirds distance to

margin; number

of pore-pairs in each poriferous zone variable;

pore-pairs nearapicalsystem extremelysmall, difficultto see_;porifer- ous zones only slightly depressed relative to interambulacra.

21

22

20

Figs. 20-22.

—

Clypeaster rosaceus dalli (Twitchell): 20, Adoral view of

U.S.N.M.648164; 21, rightsideofU.S.N.M. 648165; 22, right side ofU.S.N.M.

648166. All fromthe Caloosahatchee formation, loc. 6. All

X

i-

Periproct.

—

^Small, inframarginal, situated within 1 or

2 mm

of posteriormargin,at junction

between

fourth

and

fifth postbasicoronal interambulacral plates.

Adoral

interambulacra.

—

Primiordinal interambulacral plates

much

smaller than ambulacral plates (text fig. 20), separated

from

post- basicoronal plates

by two

pairs of ambulacral plates;

9

or 10 post- basicornal plates in each interambulacrum adorally; 16-20 plates in each

ambulacrum.

Peristome.

—

^{Central to slightly posterior,} deeply depressed, circu- lar to slightlypentagonal, opening 10

mm wide

on specimen 100

mm

long.

NO. 5

TERTIARY ECHINOIDS FROM

FLORIDA

— KIER 29

Variation.

—

^This subspecies, as is also true of the nominate sub- species, is very variable in

many

of its features.

The

test varies in shape,

from low

to highlyinflated, with angular to

rounded

marginal outline.

The

petals

may

be highly inflated or only slightly inflated.

In the apical system, all the genital pores

may

be widely separated

from

themadreporite, or

any number

of

them may

beincontact with the madreporite.

The

characters

which do

not vary are the outline of the petals, the position

and

size of the periproct,

and

the extent of the depressed area

around

the peristome.

130-

120-

110-

100

t* ⁰⁰

**

&

CO

tn So- ar UJ y- 80-

UJ

^70-

z. 60-

** O<?

O O

+

fe 50-

^

_40-

30- 20-

10- ⁺ CLYPEASTER ROSACEUSDALLI

CLYPEASTER ROSACEUS ROSACEUS

10 20

30 40

50 60

70 80 90

100 110 120 130 140 150

LENGTH

IN

MILLIMETERS

Fig. 23.

—

Clypeaster rosaceus (Linnaeus). Width of the test relative to length.

Comparison

with other species.

—

^{This subspecies is} distinguished

from

the

nominate

subspecies

by

^its wider test. In allother features these specimens are indistinguishable

from

the

nominate

subspecies.

Although

there are

some

specimens of C. rosaceus rosaceus thatare as

wide

as specimens of C. rosaceus dalli,

most

of

them

are

narrower

(see

graph

in text fig.23). ^Ihave

examined

the specimen thatJack- son referred to Clypeaster dalli

and

it can not be distinguished

from

the Caloosahatchee specimens. Jackson states that his specimen

came

30 SMITHSONIAN MISCELLANEOUS COLLECTIONS

VOL. I45

from

the

Miocene

or Pliocene of the

Dominican

Republic, but evi- dently this age determination is based only

on

the fact that the

same

species occurs in the Caloosahatchee.

Occurrence.

—

Post-Caloosahatchee, pre-Fort

Thompson

loc. 1.

Caloosahatchee formation loc. 2, 3, 6.

Cooke

_(1959, p. 34) suggested that all the Florida specimens of this species

came from

the Pleistocene Fort

Thompson

formation.

However,

neither

DuBar

nor

Wilson and

I

have

ever collected

any

specimens of C. rosaceus dalli

from

the Fort

Thompson. Wilson and

I

have

collected several specimens of this subspecies in place in the Caloosahatchee formation

(DuBar's Bee Branch member).

Types.—

Holotype,

U.S.N.M.

164670;figured specimens,

U.S.N.M.

648163-6.

CLYPEASTER CRASSUS

Kier,

new

species Plate 11, figs. 1-3; text figure24; table1

Clypeastersubdepressus Cooke, 1942 (not Gray), Journ.Paleont., vol. 16, p. 11

;

pi. 4, fig. 5.

Clypeastersubdepressus Cooke (not Gray), 1959, U.S. Geol. Surv. Prof. Paper 321,p. 36, pi. 11, figs. 2-4.

Diagnosis.

—

Species characterized

by

thick

margin and

marginally indented interambulacra.

Material.

— Three

specimens

from

Florida; 10

from South

Caro-

lina,three well preserved.

Shape.

—

^Smallestspecimen 91

mm

long,largest 126; average width

90

percent of length, averageheight 19 percent; test pentagonal with truncated posterior margin, pointed anterior with greatest width an- terior to center; strong indentations in interambulacra 4, 5, 1;

mar-

gin thick, 10 percent of length, area

between margin and

ends of petals flat or slightlydepressed; petaloidarea inflated;adoral surface

flat.

Apical system.

—

^{Slightly posterior to center, five genital pores,}

small ocular plates, madreporite star-shaped.

Ambulacra. —

^{Petals broad, short, extending} three-fifths distance

from

apical system to

margin;

anterior petal (III) slightly longer than others (see table 1), anterior paired petals (II,

IV)

shortest, posterior paired petals (V, I) intermediate; interporiferous zone approximately twice width poriferous zone; approximately

60

pore- pairs ineach poriferous zone (seetable 1).

Periproct.

—

^Inframarginal, located nearposterior

margin

;

on

holo- type (91

mm

long) opening 5.5

mm from

margin, opening irregular in outline, elongated transversely.

no. ₅

TERTIARY ECHINOIDS FROM

FLORIDA

—

^KIER 31 Table 1.

—

Dimensions of 6 specimens of Clypeaster crassus Kier, new species

Length Width Height

Thickness ofmargin

Numberof pore-pairs

Petal III II I

L III

engthof petal

II I

Florida 91 85 15 8.3 60 58 55 26.3 24.9 24.8

121 141

108 121

20 9.8

12.0

38.5 45.0

32.5 33.3

71 64 69 35.7 38.5

South Carolina 101 89 18 8.2 67 63 62 32.5 29.0 29.0

110 101 21 10.1 67 57 60 34.5 29.6 30.3

126 115 27 11.5 64 61 65 41.0 37.7 39.0

Peristome.

—

^{Central to slightly posterior,} pentagonal, pointed an- teriorly, truncated posteriorly.

Adoral

plate arrangement.

—

^Plate sutures of basicoronal plates not visible

on

all plates; basicoronal interambulacral plates separated

from

postbasicoronal plates

by two

pairs of ambulacral plates (text

fig. 24); 7 to

8

ambulacral, 3 to 5 interambulacral postbasicoronal plates in each series

on

adoral surface.

Comparison

with other species.

—

C. crassus is very similar to the livingspecies Clypeasterprostratus

and

is probably

an

ancestor of it.

Itis similar inshape, size, petal arrangement,plate arrangement,

and

position of apical system, periproct,

and

peristome. It differs mainly in having a thicker margin. In C. crassus the

margin

is 10 percent of the length,

whereas

in the average specimen of C. prostratus it is

72

percent of the length. In C. crassus the interambulacra are

much more

stronglyindented atthe

margin

in areas 4, 5, 1,

and

the poriferous zones are slightly wider.

Fig.24.

—

Clypeaster crassus Kier, new species: Adapical andadoralviews of

U.S.N.M. 648176, from Intracoastal Waterway Canal about 5 miles southwest of LittleRiver, HorryCounty, S.C,

X

^i- Basicoronal platesutures notvisible.

32

SMITHSONIAN MISCELLANEOUS COLLECTIONS

VOL. I45

Cooke

(1959, p. 36) referred his specimens of this species

from South

Carolina to Clypeaster subdepressus Gray.

However,

C. cras- sus has a

much

thicker

margin and

the area

between

its

margin and

the ends ofits petals is flator depressed

whereas

itslopes marginally in C. subdepressus. In C. crassuspetal III is

more

widely

open and

not as long relative to the other petals,

and

the test is less elongate

and

smaller.

Occurrence.

—

^Florida,

^Tamiami

^{formation,loc. 9, 10.}

^South

^Caro-

lina, U.S.G.S. 18759, Intracoastal

Waterway

canal 1.5 miles south- west of

highway

bridge near

Nixons

Crossroads, about 15 miles northeastof Myrtle Beach.

Types.

— ^{Holotype U.S.N.M.}

^{648142, loc. 9; figured specimens,}

U.S.N.M.

648143, loc. 9, 648176, U.S.G.S. 18759.

CLYPEASTER SUNNILANDENSIS

Kier,

new

species Plate 3, figure 3; plates 12, 13

Diagnosis.

—

Species characterized

by

large, low, elongate test with petal III

open

distally.

Material.

—

Fourteen specimens.

Shape.

—

^{Large, largest} specimen 157

mm

long, smallest 119

mm,

average 140

mm

^; test elongate, average width 85 percent of length

;

marginal outline pentagonal, anterior pointed, posterior truncated, interambulacra 4, 1 slightly indented at

margin;

area

between mar-

gin

and

ends of petals sloping marginally; test low, average height

20

percent of length^;

margin

thin, thickness approximately 7 percent of length_; petaloid area inflated, adoral surface slightly depressed.

Apical system.

—

^{Central to slightly anterior, five genital pores,}

small ocular plates, madreporite star-shaped.

Ambulacra. —

Petals broad, of unequal length, anterior petal (III) longest,

20

percent longer than anterior paired petals (II,

IV)

_; pos- terior paired petals intermediate in length; anterior petal open,

gap

at distal

end

of petal averaging 6.2

mm

ⁱⁿ width or 4.4 percent of length, posterior petals

open

in

some

specimens; interporiferous zone approximately twice width of poriferous zone; in specimen 139

mm

long 75 pore-pairs in poriferous zone of petal III,

64

in petal II,

69

in petal I, in specimen 119

mm

^long,

68

pore-pairs in zone of petal II, 57 in petal IV.

Periproct.

—

Inframarginal, located near posteriormargin,

on

speci-

men

130

mm

long, 4.1

mm from

posterior margin, opening irregular in outline, elongated transversely.

Peristome.

—

^{Central, shape not preserved}

^{on any}

^specimen.

NO. 5

TERTIARY ECHINOIDS FROM

FLORIDA

— ^KIER

33

Adoral

plate arrangement.

—

Plate sutures not visible

on any

speci-

men.

Comparison

with other species.

—

C. sunnilandensis is identical in all characters to C. subdepressns except that its anterior petal (III)

is

open whereas

in C. subdepressns itis closed. I

examined

35 speci-

mens

of C. subdepressns,

and

in all these specimens the anterior petal

was

closed,

whereas

in all the 12 specimens of C.sunnilandensis in

which

^this area

was

exposed the petal

was

open.

Occurrence.

— ^Tamiami

^{limestone,loc. 9, 10.}

Types.

—

^Holotype,

^U.S.N.M.

^{648135, loc.} 9; ^figured specimen,

U.S.N.M.

648134, loc. 9.

ENCOPE MICHELINI

L. Agassiz

Encope michelini L. Agassiz, 1841, Monographies d'echinodermes ^{. .} . , Mon. 2, p. 58, pi.6a,figs. 9, 10.

Encope michelini L. Agassiz. Mortensen, 1948, Monograph of the Echinoidea, vol. 4, pt. 2, p.441,pi. 70, fig.23. (See this reference forthe pre-1948 refer- ences tothis species.)

Encope michelini L. Agassiz. Cooke, 1959, U.S. Geol. Surv. Prof. Paper 321, p. 49, pi. 18, figs. 2, 3.

Encope michelini L. Agassiz. Cooke, 1961, Smithsonian Misc. Coll., vol. 142, No.4,p. 17,pi. 6,figs.5-6;pi. 7, fig. 5.

ENCOPE MICHELINI IMPERFORATA

Kicr,

new

subspecies Plate 5, figure 1; Plate 6, figures 3, 4^; text figures 25-30; table 2 Diagnosis.

—

^Subspecies distinguished

from nominate

subspecies

by

absence of posterior interambulacral lunule in

many

specimens.

Material.

—

Sixteen specimens.

Shape.

— ^{From 82}

^{to 140}

mm

long.

Broad

withwidth varying

from 94

to 101 percent (average 96) of ^{length; test} very

low

varying

from

7 to 12 percent (average 9) of length; greatest width posterior to center, anterior

margin

rounded, posterior sharply truncated; great- est height posterior to center; ambulacral notches well developed

on some

specimens (text figs. 25, 30), absent

on

others_; posteriorclosed interambulacral lunule present in six of twelve specimens preserving area

where

it

would

occur, irregularly developed, in

some

specimens opening very small (text fig. 26), inothers quite large (text fig. 28), usually irregular in shape, unsymmetrical; in one specimen opening in adapical surface but

none

in adoral^; in six specimens

no

lunule (text figs. 25,29, 30); adoralsurface ^flatto slightly depressed except for slight elevation

between

peristome

and

periproct;

margin

sharp.

Apical system.

—

^{Slightly anterior,} madreporite large, star shaped,

29 30

Figs. 25-30.

—

(See opposite page for legend.) 34

NO. 5

TERTIARY ECHINOIDS FROM

FLORIDA

—

^KIER 35 five genitalpores, genital pore 5 eccentric to right

on most

specimens.

Ambulacra. —

^{Petals broad, closing clistally,} interporiferous zone wider in petal III than in other petals; anterior petal III, posterior paired petals

(V and

I) of approximately

same

length (see table 2)';

anterior paired petals shorter than others, in

most

specimens petal II shorter than petal

IV;

in smallest specimen

76

pore pairs in petal III, 59in II,61 in IV,

82

in

V

or I; in larger specimen 100

mm

long

92

pore pairs inpetal III, 70 in II, 81 in IV, 118 ⁱⁿ

V

or I.

Table^2.

—

Encope michelini imperforate! Kier, new subspecies Lengthof test

109

ill 39

II

Lengthofpetal

IV 31

V

41

I 41

100 32.5 27.3 29.2 36

106 33 25.1 25.1

115 36 27.2 29.4 36 36.5

122 38 32.3 32.5 39.5 39

82 23 17.1 18.4 22.3 22.4

90 32.5 16.8 17.8 22.8 ,

.

Adoral

plate arrangement.

—

^{Sutures not visible}

on

specimens.

Periproct.

— ^Opening

longitudinal, located one-third distance

from

peristome toposterior margin.

Peristome.

—

^{Central, circular.}

Comparison

^zvith

nominate

subspecies.

—

^{This subspecies is similar}

in all respects to the

nominate

subspecies except that its posterior closed lunule is quite small or entirely absent. In one-half of the specimens of

Encope

michelini imperforata the lunule is absent

whereas

in the

nominate

subspecies it is apparently always present.

I

examined

186 specimens of the nominate subspecies,

and

in all of

them

this lunule

was

present.

Remarks. —

^This subspecies, as with the nominate subspecies, is

very variable in the shape of the test.

The

ambulacral notches are very well developed in

many

of the specimens but completely absent in others.

Occurrence.

—

Post-Caloosahatchee, pre-Fort

Thompson,

loc. 1.

Caloosahatchee formation, loc. 4, 6, 7.

Tamiami ("Buckingham"

facies) formation, loc. 23.

Types —

^Holotype,

^U.S.N.M.

^{648167, loc.} 2; ^figured specimens, Figs. 25-30.

—

Encope michelini imperforata Kier,

new

species: 25, U.S.N.M.

648169, loc. 7; 26, U.S.N.M. 648167, loc. 2; 27, U.S.N.M. 648170, loc. 4; 28,

U.S.N.M. 648168, loc. 6; 29, U.S.N.M. 648171, loc. 4; 30, U.S.N.M. 648172, loc.4. Allapproximately

X h

36 SMITHSONIAN MISCELLANEOUS COLLECTIONS

VOL. 145

U.S.N.M.

648169, loc. 7;

U.S.N.M.

648170, 648171, 648172, loc. 4;

U.S.N.M.

648168, loc. 6.

ENCOPE TAMIAMIENSIS

Mansfield Plate 14, figures 1-6; text figures 31-35

Encopemacrophora (Ravenel) (part), Clark and Twitchell, 1915, U. S. Geol.

Surv. Mon. 54, p.206, ^pi. 94, figs. la-f.

Encope macrophora tamiamiensis Mansfield, 1932, U. S. Geol. Surv. Prof.

Paper 170-D, p.48, pi. 17, fig. 8.

Encope michelini Agassiz. Barry, 1941, Proc. U.S. Nat. Mus., vol. 90, pi. 65, fig.4.

Encope tamiamicnsis Mansfield. Cooke, 1942, Journ. Paleont., vol. 16, no. 1, p. 20

Encopetamiamicnsis Mansfield. Cooke, 1959, U. S. Geol. Surv. Prof. Paper321, p. 48, pi. 17, figs. 3, 4.

Diagnosis.

—

Species characterized

by

thin margin, smaller lunule,

and more

posterior apical system.

Material.

— ^More

^{than 1,000 specimens.}

Shape.

— ^Length

^varying

^from

^{7.6 to 122}

mm;

^width varying

from

slightly wider than high to

80

percent of length, with average specimenslightly

narrower

than long (text fig. 31) ; marginal outline subcircular, truncated posteriorly; five ambulacral notches; anterior notch slight, posterior notches deep;

on

smallest specimens

no

notches; posterior notch well developed, present

on

all specimens, elongate, irregular in shape

and

size; test low, height varying

from

10 to

20

percent with

an

average of 14 percent of the length (text

fig. 32), greatest height posterior of center at anterior edge of lu- nule;

margin

very sharp with test thin at

margin;

adoral surface evenly concave.

Apical system.

—

^{Anterior (text fig.} 33) ^distance

from

anterior

margin

to apical system approximately

40

percent of length of test

;

large central star-shaped madreporite with five genital pores, genital pore 5 usually eccentric toright (pi. 14, fig. 5).

Ambulacra. —

^{Anterior petals II, III,}

^IV

lanceolate, straight, of approximately equal length, with interporiferous zones wider, equal to or

narrower

thanporiferous zones; posteriorpetals

V and

Ilonger, curving posteriorly, interporiferous zones

narower

than poriferous.

In specimen 75

mm

long

70

pore-pairs in each poriferous zone in petal III; 62 in petals II or

IV

^;

80

in petals

V

^{or I; rate of intro-}

duction of

new

pore-pairs decreases with

growth

(text fig. 34.).

Periproct.

— ^Opening

^{small, elongate, located at anterior edge of}

lunule atinner

margin

of first pair of postbasicoronal plates in

most

specimens,in several not in lunulebutanterior toit.

NO. 5

TERTIARY ECHINOIDS FROM

FLORIDA

—

KIER ₂₎₇ Peristome.

—

^{Anterior, small opening,} subcircular; food grooves bifurcatingnearperistome,

one

or

two

lateralbranchestoeachgroove.

Adoral

plate arrangement.

—

Basicoronal plates small (textfig. 35), interambulacral plates larger than ambulacral, posterior interambu- lacral plate considerably larger than others_; paired interambulacra o o IIO-j

o

100 ^o

OO

o o

90- o°

oo o

to 80- o

ce o o

LJ Hi

70"

2

o^ +

Zj

60-

o⁺

_j

S

_50-

^Oo

z

_o

x ^40-

^{o o}

H

⁺

Q -~

⁺

^

^30-

&

⁺

20- o

o»

10-

o

o o

+

ENC0PE

TAMIAMIENSISMansfield

ENCOPE

MACROPHORA(Ravenel)

10

20 30 40 50 60 70 80 90

100 110 120

LENGTH IN MILLIMETERS

Fig. 31.

—

Encope tamiamiensis Mansfield, Encope macrophora (Ravenel).

Width of test relative to lengthof test.

separated

from

basicoronal plates

by

first pairof postbasicoronal

am-

bulacral plates_;posterior interambulacrumincontactwithbasicoronal plate; interambulacra with 3 or

4

postbasicoronal plates in each

column

^; ambulacra with

6

or 7postbasicoronal plates toeach column.

Growth. — ^On

^{the smallest specimen, 7.6}

mm

^long, the posterior notches are veryslightly developed

and

there are

no

anterior notches.

The

posterior lunule is very small.

The

first anterior notches occur ina specimen 14.2

mm

long,

where

they are only slightly developed.

38 SMITHSONIAN MISCELLANEOUS COLLECTIONS

VOL. 145

The

posterior petals are straight in all the smaller specimens (pi. 14, fig. 1), but curve posteriorly in all the specimens over 17

mm

long.

There

are

no

genital pores in

any

of the specimens less than

20 mm

long.

12- + +

II ^-

+ »

* 10-

+

LlJ .

h- 8- LU

2 3

^7-

_i

S _{6- +}

z

I- 5-

X ⁺

^{+ +}

o

LJ 4-

X

⁺•f

3-

%*

+

2-

l-

+

10

20 30 40 50 60 70 80 90 100

110

LENGTH IN MILLIMETERS

Fig. 32.

—

Encope tamiamiensis Mansfield. Height of test relative to length oftest.

Variation.

— ^The

^{posterior lunule is very variable in its outline}

and

size. In

many

of the specimens it is not symmetrical. Genital pore 5 ^is eccentricto the rightin

most

of the specimens. In

a

popu- lation of 25, 23 of the specimens

had an

eccentric pore

and

in only

two was

the pore not eccentric.

no. ₅

TERTIARY ECHINOIDS FROM

FLORIDA

— ^KIER ₃₉

< _O

<

a.

o

cc u.

CO en UJ

UJ

o

CO

40

1

o

<

230

o

en

£E UJ

^20 <

o

f±fio CO

>

CO

<?*?

c? ^*- _<D

o ENCOPETAMIAMIENSIS Mansfield + ENCOPE

MACR0PH0RA

(Ravenel) 10

20 30 40 50 60 70 80 90

100 110 120

LENGTH

IN

MILLIMETERS

Fig. 33.

—

Encope tamiamiensis Mansfield, Encope macrophora (Ravenel).

Distanceofapicalsystem fromanterior marginrelative tothelength ofthe test.

IIO-j

M

₁₀₀

cc:

o H

^90-

CO _! 80-

< H u

a. 70-

•z.

CO 60-

cr

2 ⁵⁰

iii

IE

O

^40-

Q_

ll

O

^60-

cn CD 20-

2

2: 10-

10

20 30 40 50 60 70 80 90

100 110 120 130

LENGTH

IN

MILLIMETERS

Fig. 34.

—

Encope tamiamiensis Mansfield.

Number

of pore-pairs in petals I or

V

relative tolength of test.

40 SMITHSONIAN MISCELLANEOUS COLLECTIONS

VOL. I45

Comparison

with other species.

—

E. tamiamiensis is similar to

Encope macrophora

(Ravenel)

from

the Late

Miocene

of

South

Carolina.

However,

in E. tamiamiensis the

margin

is thinner, the lunuleis smaller,

and

the apical system is lessanterior (text fig. 33).

Furthermore, in E. tamiamiensis the anterior paired petals (II

and IV)

are less curved posteriorly.

Both

species

have

the

same

length- widthratio (text fig. 31).

Occurrence.

— Tamiami

formation (typical), loc. 9, 10, 11, 14, 15, 17, 18, 19.

Fig. 35.

—

Encope tamiamiensis Mansfield: Adoral view of U.S.N.M. 648141, fromtheTamiamiformation, loc. 31,

X

^1-

Tamiami

formation

("Buckingham"

facies), loc. 20.

Tamiami

formation (barnacle-echinoid-oyster facies), loc. 26, 27, 28, 29, 31,32.

Types.— Figured

specimens,

U.S.N.M.

648137, loc. 27;

U.S.N.M.

648138, loc. 26;

U.S.N.M. 648139;

loc. 11;

U.S.N.M.

648140-1,

loc. 31.

MELLITA ACLINENSIS

Kier,

new

species

Plate 15, figures 1-3; text figures 36-41; tables 3, 4

Diagnosis.

—

^Species characterized

by

five ambulacral lunules.

Material.

—

^{Eleven nearly complete specimens}

^{and many}

^fragments.

NO. 5

TERTIARY ECHINOIDS FROM

FLORIDA

— ^KIER

41 Shape.

—

^{Smallest specimen 16.5}

^mm

^{long, largest 73}

mm

^(see

table 3 for dimensions) ;

margin

subcircular except for truncated posterior

margin on some

specimens; width approximately equal to length; test very

low

with thin sharp

margin

; adoral surface flat to slightly concave; 5 elongate ambulacral lunules inlarge specimens, lunule in

ambulacrum

III smaller than others; lunule in posterior interambulacrum very elongate, extending far

between

petals.

Apical system.

—

^{Slightly anterior, distance}

^from

^anterior

^margin

to apical system approximately 45 percent of length of test; large madreporite; four genital pores.

Table ^3.

—

Dimensions of ¹¹ specimens of Mellita aclinensis Kier,

new

^species

Length Width Height

mm

ram

mm

16.5 16.3 2.4

21.8 22.5 2.7

22.7 23.0 3.1

24.0 23.6 3.2

25.7 25.5 3.3

30.0 32.7 4.0

31.7 31.4 4.1

35.0 37.0 5.0

44.0

73.0

56.0 5.6

III

Lengthofpetal

II I

mm mm mm

4.0 3.8 4.3

4.4 6.1

5.7 5.0 6.3

5.9 5.4 6.4

6.0 5.5 ..

.

7.9 7.4 9.1

8.5 8.3 8.9

9.2 7.7 9.8

10.5 10.0 12.1

11.2 11.3 15.3

Ambulacra. —

^{Anterior petals II, III,}

^IV

lanceolate, straight, petal III longer, extending almost two-thirds distance

from

apical system to anteriormargin, petals II

and IV

only

halfway

to

margin

;

posterior petals

V and

I longerthan anterior petals, not straight but curving posteriorly; in all petals poriferous zone equal in width to interporiferous

; petals almost closed; in specimen 35

mm

long,

34

porepairs in single poriferous zone ofpetals II, III, IV,

47

in petals

V

or I. Adorally, five pairs of food grooves extending

from

peri-

stome

to near

margin

(pi. 15, fig. 3) ^; area circumscribed

by

pair of grooves

expanding

^distally with greatest width near lunule, con- stricted distal tolunule; areabroad

between

adjacentpairsof grooves.

Secondary

pores difficult to see in

most

specimens, apparently con- fined to area circumscribed

by

food grooves.

Periproct.

— ^Opening

^{small, elongate, located at anterior edge of}

lunule.

Peristome.

—

^{Anterior, small,} subcircular to pentagonal, food grooves bifurcating near peristome.

42 SMITHSONIAN MISCELLANEOUS COLLECTIONS

VOL. 145

Adoral

platearrangement.

—

Basicoronalplates small (textfig. 36) ;

adoral-most plate of interambulacrum 5 considerably larger than other basicoronal plates; paired interambulacra separated

from

basi- coronalplates

by

one pair of ambulacral plates, three postbasicoronal plates in each

column on

adoral surface; first pair ofpostbasicoronal interambulacral plates elongate; posterior interambulacrum in con- tact with basicoronal plates; half of periproct within basicoronal in-

terambulacral plate; first postbasicoronal plate of posterior inter-

ambulacrum

extending lengthof lunule.

Fig. 36.

—

Mellita aclinensis Kier, new species: adoral view of U.S.N.M.

648192, fromthe Tamiamiformation, loc.27.

X

^2.

Aberrant

specimen.

—

^{In one of the specimens} the anterior

ambu- lacrum

(III) is not fully developed (text fig. 37).

The

plate ar-

rangement

is

normal

adoral to the tip of the petal, but there are

no

ambulacral plates

between

the apical system

and

the tip of this petal.

Evidently production of ambulacral plates ceased after the first

few

petaloidplates

had

been

formed and

the resulting

gap was

filled

by

the prolongation of the interambulacral plates

which would

normally be adjacent to this

ambulacrum.

Ontogeny.—

^-The ambulacral lunules are not present in the smallest specimen, 16.5

mm

long (text fig. 38), but there are slight marginal notches in ambulacra II

and IV and more

developed notches in

V

and

I. In a specimen 21.8

mm.

long (text fig. 39) there are deep notches in the paired ambulacra, with the notches in ambulacra II

and IV

almost closed,

and

in a specimen 24.0

mm

long (textfig. 40)